Fluid-heating device and method of operating same



J. A. BROWN ET AL' Filed April 19; 192

M um M z a 1 u "1mm: fl 4 m l n I q 5 lizzll n J k v 6 B May 28, 1929.

FLUID HEATING DEVICE AND METHOD OF OPERATING SAME Patented May 28, 1929.,

earran stares ear James A. BROWN AND WILLIAM J. HANDLEY, or zmcxson, MICHIGAN, nssrenons T HANDLEY-BROWN HEATER co umnar, on ancxson',,m1cnrean,a coaroaa TION OF MICHIGAN. I

F UInHE-ATINenE-vmn AND METHOD or ornaerme smn.

Application filed. April 19, 1926. SeriaPNq. 103,174,

Our invention relates to a fluid heating device and method of operating the same. It relates particularly to theuse of gas as a heating medium, and has to do with the provision of a novel and eflicacious means for v transferring the heating units 'to the fluid to be heated, whereby the fluid is maintained at an approximately uniform temperature with a relatively low rate of gas consumption and a minimum total consumption of gas.

In the past, various methods and means have been used for heating fluids, where the fluid is received in a suitable container in a cold state to be subsequently heated and transmitted for various uses, some of which have involved the application of a heating, medium directly to the base of the container, some of which have contemplated the passing of fluid through a series of coils to present a large and quick actingheating surface, and others of which have passed the heating-medium or gases through conduits positioned wit in the fluid container. Theseefforts at fiui heating have been numerous and qulte varied, but the satisfactory and efiicient results havenot been obtained with reference to either efiicient exchange of the heat units or efiicient, low and constant rate of fuel consumption.

failed because, for one reason, they have failed to properly pass theheating medium through or in contact with the liquid in the container in such a manner and at; such a rate as to transfer a large portion of the heat units to the liquid. Inother words, the at tempts have generally been directed pr marily to the heating of the water or llquid in hot water tanks or similar receptacles cit-her quickly or by a large amount of fuel at infrequent intervals, and secondarily, to

the utilization of substantially all the heat.

up their heat units to heat the the liquid within the container or heater These efforts in the past have apparently tion of the heating medium or heating gases into the; liquid container in such a manner that the heatunits are given up gradually, and substantially completely to. the liquid within the container, and all unnecessary draft through the flue is avoided; Furthermore, by our device the burner is operated at a relatively low rate of fuel consumption at all times,-whereby sufiicient hot li uid is available at all times, whenever desire with little appreciable increase in the rate of gas consumption, p

More specifically, we have found that by passing the heating gases throughout the length of 'the"heater ,or container, whereby the gases will uniformly and completely give iquid, that may be uniformly and constantly maintained at the desired temperature, with a very small amount and rate. of fuel consumption. Therefore, we preferably providea container of relatively long cylindrical dimensions, in which is positioned a flue or conduit whose length is very great as compared to its cross section, and which conduit extends the length of the container and returnsto a position as low or lower than the intake. A relatively small gas burner is placed at the entrance of this conduit, and a thermostatforcontrolling the amount of gas admitted to the burner is positioned in the bottom of thecontainer adjacent the entrance for the cold water or fluid. The cold water inlet is arranged in a novel manner with respectto' the heatmg conduits and the thermostat,

whereby the admission of the gas is accurately and instantly controlled.

Alow consumption burner is a great advantage to gas companies for the reason that it permits cutting down the size of the gas mains, and tends to eliminate peak loads at certain times of the day. By our arrange ment of heating'apparatus, the movement of the gases in the'heating conduit is reducedto a minimum, whereby only a relativelysmall low consumption burner is required and utilized to keep the; fluid in the containerat the required temperature.

In the drawings:

Fig.1 is a vertical longitudinal section through a hot water heating tank embodying I the features of our invention and'showing I the form and; arrangement of the conduit for let and the heating gas conduit.

Fig. 3 is a horizontal cross section through a tank, similar to Figs. 1 and 2, but, showing a. slightly modified form wherein two separate heating gas conductingconduits areutilized-instead of one.

This invention is particularly adapted to the heatingjof water in what is known as the 3 storage type of hot water heater, but it will be understood that it is equally applicable to the efii'cient heating of water or-other fluids in other types of containers. The invention is illustrated in combination with the stand ard type of domestic hot water heater of general cylindrical shape',and of 'a length relatively long with respect to its cross section.-

The outer shell of this'tank may be desig-= natedd, and may consist of sheet steel of suitable gage. A second shell 2 is centrally po sitioned: within the outer -shell,and a space" between the two shells .is filled, up with, or p p able-valve 12 may 'be'insertedbetween the thermostat 11 and the burner 6 making it carries a suitable insulatingmaterial 3-. '1 Desi'gnedto be centrallypositioned wlthin the inner shell 2 is a U-shaped tubing 4, both legsof whichextend through the bottom of" the tank and the upper closed end of which reaches approximately to the'top of the inner shell. This tubing or conduit .is of relatively small cross section with respect to its length,

and is. preferably of the same diameter throughout. As shown in Fig. 2- the tubing is positioned centrally of the tank, and as shown in 'Fig. 1 the two legs spaced equi-distantly from the walls of the tank. This positioning, size and arrangement of the tubing 4, for conducting the heated gases is a very important feature ofour invention, as it makes possible a maximum of efliciency in transforming the heat units from the heated gases to the water, and'also makes possible the construction of a compact heating tank of extreme simplicityl: Y r r a short distance below the bottomof the tank, and is ada'pted to receive the upper end of a su-itable, single, low consumption burner 6.

The intake 5 or the conduit 4 eitends only This burner is positioned-adjacent the inlet opening of the conduit'5 in any suitable man- 7 ner. whereby the relatively small flame ema- 'nating therefrom is-confined practically entirely within the lower end of such conduit.

The other leg 7 of this tubing or conduit 4 is adapted to conduct the cooled exhaust gases away from the heater and preferably extends through the bottom of the tank and downwardly to a position below the bottom oftheintake leg 5. The lower end of this exhaust gas conduit 7 may be, if desired, connected to a suitable flue by means of an interconnecting moisture trap 8. However, such an exhaust flue is unnecessary in the present construction because of the extremely low rate of gas consumption, and the arrangement of the hot gas conduit within the tank. Hence it will be obvious that the tankmay be placed anywhere in the basement or building .Without a chimney connection at'all.

The cold water inlet to the tank is preferably by means of a suitable pipe 9, which extends downwardly through the top of the tank and approximately centrally thereof, as

clearly shown in Figs. 1 and 2. This pipe extends the length of the tank and terminates 5 and 7 of'the conduit 4. I v

A thermostat couple 10, forming a part of a suitable thermostat 11,-extends inwardly transversely and centrallyof the tank and in its preferred locationprojects between the conduit legs 5 and 7 and is positioned slightly below the lower end' of the water pipe 9. The thermostat llmay be of any standard type, containing a suitable valve-actuated by the relative expansion ofthe couple-to control the rate of flow of the gas to the burner. A suitpossible to control the'maximum amount of gas to be supplied to the burner at any time.

A suitable drip pan 13' may be positioned be low the moisture trap andsupported by the legs of the tank; Ahot water outlet pipe 14 is positioned in the topof the tank, as clearly shown in Fig. 2.

.It will be understood that although the U shaped conduit 4 may be of any desired relative size in cross section. inthe present heating apparatus and method of heat transfer, the conduit 4 is of relatively small cross section in proportion to its length, and in about the proportions as illustrated in the drawings. Therefore, instead. of enlarging the heating flue for use in tanks of larger capac ity, it is preferable to provide a plurality of tubes'4, and burners, as illustrated in Fig. 3. Where'two or more separate conduits "are used they are' preferably located centrally and symmetrically with reference tothe circumference of the heater, and thecold water of the legs of the conduits. The thermostat coupleisalso preferably positioned centrally of'the heating gas flues as well as at a point adiaejent the bottom of the cold water inlet.

In" operation, the incoming cold water having' affected the thermostat to open the gas valve, the flame issuing from the single small to a flame sufficient to cause heat transfer and the raising of the temperature of the water within the tank. This burner flam due to the arrangement. of the heating ue and iinlet pipe is' preferably positioned centrally "burner is changed from a suitable pilot lightmethod of conducting the gases, is designed to operate at a relatively low rate of gas consumption, approximately. 6 cubic feet per a hour, as compared with an average of about burner. The hot gases rising inthe small v be operated to supply hot water at the desired straight sided leg 5 of the conduit gradually and progressively impart their heat;units to the water in the tank or boiler, the rate of transfer of heat units gradually diminishing as the gases approach the top or curve of the conduit. By the time the gases have passed through the length of the relativelylong flue and approach the lower end of the exhaust conduit, which is positioned beneath the in-- .take of the inlet conduit, there has been a maximum exchange of heat units whereby the temperature of the exhaust gases will be approximately the same or only slightly higher than the temperature of the tank.

,Due to the novel arrangement of the intake and exhaust flues, the positioning of the inlet water pipe and thermostat,-and the passing of the gases in the relatively small column from the bottomto-the top of the tank and g our device for t-wo realsonsr One is that no return, it is possible to maintain the temperature of the water at the top and bottom of the tank approximately constant.' In actual practice, under normal conditions,it is possible to maintain the water at the top at a temperature of about 150 F., and the temperature at the bottom of the tank at about 140 F. Due to this relatively long column of restricted cross section, the use of a low consumption burner, and the maintaining of.

the temperature approximately constant at the bottom and top of the tank, the,movement of the gases through the tube is reduced to a minimum andthe gases travel at an extremely low but positive rate to thereby give up all of their heat units to the water within the tank. \Vhen the water has reached the desired temperature the thermostat will be affected to restrict t e flow of gas to the burner and the burner; flame will be only such as to compensate for theloss by radiation.

It willthus be seen that we have provided a novel gas water heater of the storage type of an extremely simple, compact and inexpensive construction, and which heater may temperature at all times and with only a relatively small amount of gas or fuel and ate. relatively low and 'approxin'lately constant rate of consumption. It will further be seen that use of a low consumption burner of .this type, makes it possible for the gas company to solve some of their greatest present day problems in that such a burner permits the material reduction of the size of gas mains and also tends to eliminate'peak loads at certain times of the day.

delays the heated pro We may add that a great success of our unit is, in our gudgment, due to the practical elimination o excess ventilation or draft through the long, '(narrow, inverted, U-like.

flue. In the types of center fines that are ordinarily used the fiues are large and are open at the top of the tank. The result is that there is a verylarge proportion at cold air drawn up through these which either has to be heated in efiecting the heat exchange, or else abstracts heat from the contents of the tank. With our construction the doubling of the flue back upon itself and the discharge of the products of combustion below the burner results in asort ofa balanced column arrangement that is not'conducive to enforced ventilation or draft through the-flue. This i .is especially true with a relatively long and narrow flue, such as we have f shown. The

rising heat,- which by reason of the'small' consumption burner is not at any time very great, is required to push this long and nar row column clearlfidownthrough the return flue in order to discharge the products of com bustion. The result is that the ventilation through this type,v of'flue is very slight, especially with this low consumption bui'ner.

This is very advantageousin the operation of port combustion. This form of operation has a second advantage in that it'obviously ucts of combustion as long as possible in their movement through. the longflue, and consequently the utmost of theheat units is abstracted from the products {offcombustion before they are discharged.

It will be obvious that if a larger cross section flue of shorter length is used that the differential in pressures t'endin .to accelerate the movement ofair and pro ucts ofcombustion'throu h the flue, will be much greater} 'It' will also be obvious that if a large consumption. burner is .utilized j. that this differential in pressures" which acceleratesthe draft will be much greater. other'important factor is that this type of fluev is very advantageously. suited to coop erate with the low consumption burner. In 1 feet the burner of the consumption we have named "would be outof the. question with most fines, for by reason of the draft through the flues aburner of this consumption would not be practical, asit would not carry enough heat to effect the necessar heat exchange under the condition obtaining in such fiues.

By the retardation of the ventilation in the way that we have pointed out, it is possible to very effectively use a low consumption burner, such as we havedescribedfand we find such-a low consumption burner is notonly desirable with such a flue by'reason of lessening the necessary size of gas mains and peak loads, but actually much more economical in the operation of this type of flue because it is conducive to the most sluggish circulation which is permissible in clearing the products of combustion, and thereby efl 'ects the greatest possible heat-exchange."

Another valuable feature isthat w1t ha low consumption burner there is very little likelihood of-scale depositing on the dues,

- scale toadhere. J

for the reason that the flues at any given point rarely-reach the temperature at which scale deposits. Furthermore, with'our construction with-the inverted U-like flue nearly all the surface is'a 'vertical'one; and-consequently there is ver'yflittle chance for the -What we claim is: 4 Y

1. A water heating apparatus of the type described, comprising an insulated storage container of relatively vlarge-jcapz'lcity, one or more conduits within the c'ontainervfor conducting the heated gases and having intake and exhaust legs extending approximately thelength of the container, said intake and exhaust legs being of thesame size and di-; mensions throughout, and asingle burner I for the intake leg of each.conduit,sai'd'burner' having a relatively low fuel consumption practice and to. said having intake andexhaust' legs""extendingapproximately the full length'of the contamer and-positioned interiorly thereof, said exhaust legsextending through the bottom of the container 'to a position. below the intake to retard the flow of gases-"through the conduit, and an inlet conduitextendingdongitudinally and centrally from, the top of the container in close heat exchange relation with the legs of the conduit for discharging liquid to be heated at a point adjacent the bottom of the.'container.'-

3. A' waterheating apparatus bf the type described, comprising in combination a storage container designed to hold. a'relatively large constant supply of; water compared to the heat units available, a conduit for con-- ducting the heated gases having intake and exhaust legs extending approximately the fulllength ofthecontainerand positioned centrally thereof, said exhaust leg extending through the bottom of the container to a position below the intake-to retard the flow of gases through the conduit, an inlet conduit for the discharging liquid .to be heated at a 'point'adjacent the bottom of the container, p

and a burner for said intake leg having a relatively low fuel consumption compared to standard practice, said exhaust leg being lower 1; V mosphere.

heating apparatus of the .stor

4 wardly ada ted to dischar e the exhaust gases di- Irect y to the atmosp ere. v j. 4. A water heating-apparatus of the type described, comprisin an insulated container designed to holda re atively large supply of water-compared to the heat units available, an inverted U-shaped conduit having intake and exhaust legs extending approximately thelengthof said container and through the bottom thereof, said conduit being of relatively' small cross section throu hout to ret'a'rd the flow of gases to an extent .just sufficient to, support combustion, and a condensation trap at the bottom of said exhaust leg,

the gases are exhausted at a point an the intake and directly to the atwhereby 5. The method of heating liquids instorage tank's, which comprises confining a relatively large mass ofliquidto an upright body of relatively small crosssection,- passing heating gases derived from low consumption fluid fuel upwardly and returning the gases downwardly through the lengthof said body'of liquid of relatively small cross section, automatically controlling the rate of. consumption, maintaining said body of liquid'by carrying the'liquid supply in close heat exchange relation with said upward and downward path of heated gases and introducing the liquid supply ata point near the bottom of SaICl mass of liquid and adjacent said controlling means, and restrictinglthe gases in such path to a column of relatively small cross 7 section whereby a large percentage of the heat units of the gases are transferred to the liquid at the bottom of said mass of liquid, only a small percentage of the heat units transferred-to the mass of liquid atthe top or hottest part of the column, and substantially completel transferring'the remaining heat units to tie liquid as the gases pass doWnto the lower portionof said column of liquid. 6. A

water heating apparatus. of the storage, continuous supply type; comprising an upright storage "container of a relatively small cross section compared to its height, and designed to hold arelatively large constant supply of Water compared to the. heating units available, insulating means surrounding said container to prevent radiation losses, one or more conduits within the c'on- 'tainer for conducting the heating gases having intake and exhaust legs extending approximately the length of the container, 'a

burner for the intake leg of each conduit having a relatively low consumption compared to standard practice, said conduit having-a relatively small cross section substantially throughout whereby the heat units from the gases are gradually and substantially com- .pletely transferred to the water and have a relatively slow rate of movement.

7. water heating apparatus of, the

storage, continuous supply type, comprising a storage container, one or more conduits within the container for conducting the heated gases having intake and exhaust legs extending approximately the length of the container, a single burner for the intake leg of said conduit, or conduits, having a-relativel low fuel consumption compared to stan ard practice, said conduit having a relatively small uniform cross section substan- 1 tially throughout itslength, an inlet.conduit extending longitudinally from the top of the container in close heat exchange relation-with the legs of said conduit and terminatin'g'adjacent the bottom of said containeryand a thermostat element for controlling the s'u'pply of fuel to said burner,vor burners, having an element rojecting intothe container and 4 positioned etween thetwo legs of the con duit and adjacent the end of said inlet conduit.

8.- A waterheating apparatus of the; storage, continuous supply type, compris- 'ing -arr upright storage container. of rela.-'

tively small cross section and designed to hold a relatively large suppl of water compared to the heatunits availa le, insulatingmeans surrounding said container to prevent radiation losses, one or more conduits within the container for'conducting heated gases and having intake and exhaust legs extending approximately the length of the container, a

burner for the intake leg of said conduit, or conduits, having relatively-V low fuel consumption compared to'standard practice and to said body'of water in said container, an inlet cpnduit extending longitudinally from the top in close heat exchange relation with said first named conduit and terminating adjacent the bottom of said container, means for controlling the low consumption fuel supply to said burner,'or burners, positioned adjacent the end of said inlet conduit, said first named conduit having a relatively small cross section whereby theheat units from the gases, when the low consumption burner ,is operating, are transferred-at relatively great rate to the cold wat'en fin the ower part of the 0on tainer, transferred'at a relatively slow rate to the hot water in the top part of the container, and the remaining heat units in thereturn leg of the conduit'are transferred substantially completely to the said cold water erating to provide- Water for current use, a conduit within the container for conducting heated gaseshaving intake and exhaust legs extending approximatel the length of the container, and a p fluid uelconsuming heating element positionedadjacent the intake leg of said conduit, said heating elementhaving a relatively lowrate of fuel consumption compared-to standard practice.

" 10.- A water-heating apparatus of the'storage continuous supply type, comprising a storage tankof relatively small cross'section 7 compared to its height and provided with heat insulation on its outside, and designed to hold a relatively large constant supply of water, inlet and outlet connectionsfor said tank for supplying and drawing off water for current use, a conduit within the tank of relatively small cross-section for conducting] heated gases-having intake and exhaust legs extending approximately the length of the tank, and

a fluid-fuel consuming burner positioned un-' derthe intake leg and arranged to have when burning at its maximum a relatively low rate of fuel consumption compared withstandard practice. 4

11. A water-heating apparatus of the storage continuous supply type, comprising, a storage tank of relatively small cross. section compared to its height and provided with heat insulation on its outside, and designed to hold a relatively large constant supply c of Water, inlet and outletconnections for said tank for supplying and drawing off water for currentuse, a conduit within the tank of relatively small cross section for conducting heated gases 'havin intake and exhaust legsopening' through the ottomportion of the tank Whereby the intake and-exhaust are substantially in the same horizontal plane, said legs being of a combined length -substantially twice the height of the tank, and a fluid-fuel consuming burnerpositioned under theintake leg and arranged tohave when burning at its maximum a relativelylow rate offuel consumption compared to standard practice. t

12. A water-heating apparatus of the storage continuous supply type, comprising a storage tank of relatively large'capacity and provided with heat insulation on its outside,

and designed to hold a relatively large constant supply of water'compared to the heat units available, inlet and outlet connections for said tank for supplying and drawing ofi water for current use, a conduit within the tank of relatively small cross section for conducting heated gases,-said conduit having intake and-exhaust legs extending throu hthe bottom portion ofthe tank whereby t e in-- take and exhaust are substantially in the same horizontal plane and said entire conduit with in the tank being of a relatively great length and at leastv twice the approximate height of the tank, anda fluid-fuel consuming burner positioned under the intake leg and arranged to have when burning at its maximum a relalation whereby the heat units of the gases are -tively low rate of fuel consumption compared substantially completely transferred to the with standard practice and to said body of liquid. 1 water, the small cross-section and great length In testimony whereof we aflix our signa- 5 of said conduit being such as to retard the tures.

'flow of gases from the low consumption burn JAMES A.- BROWN.

or to anextent just suflicient to cause circu WILLIAM J. HANDLEY. 

